-LRB- CNN -RRB- -- NASA plans to capture an asteroid and start sending astronauts aloft again by 2017 , even with a tighter budget , the U.S. space agency announced Wednesday .

The Obama administration is asking Congress for just over $ 17.7 billion in 2014 , down a little more than 1 % from the nearly $ 17.9 billion currently devoted to space exploration , aeronautics and other science .

The request includes $ 105 million to boost the study of asteroids , both to reduce the risk of one hitting Earth and to start planning for a mission to `` identify , capture , redirect , and sample '' a small one . The plan is to send an unmanned probe out to seize the asteroid and tow it into orbit around the moon , where astronauts would study it .

`` This mission allows us to better develop our technology and systems to explore farther than we ever have before ... to places humanity has dreamed of for as long as I 've been alive , '' NASA Administrator Charles Bolden told reporters .

The Obama administration has said before that it wants to send astronauts to explore an asteroid by 2025 and to Mars by 2030 .

Forget falling stars : NASA plans to catch an asteroid

Wednesday 's budget request would include another $ 20 billion to study near-Earth asteroids -- doubling the current spending on that effort . The funding is aimed not only at finding a suitable asteroid to explore , but also at `` protecting the planet , '' Bolden said .

That concern got new attention after February , when a nearly 150-foot asteroid passed within 18,000 miles of Earth . That one was expected -- but the same day , an unrelated , 45-foot space rock plunged into the atmosphere and exploded high over southwestern Russia , injuring an estimated 1,200 people .

White House science adviser John Holdren told a congressional committee in March that as few as 10 % of asteroids more than 150 yards wide -- which he called `` potential city killers '' -- have been detected .

NASA 's budget request includes $ 822 million for the agency 's Commercial Crew Program , its push to resume U.S. space flights through private companies by 2017 . Bolden called that the `` bottom-line '' figure , warning that any cuts would mean delays . NASA has already hired the unmanned SpaceX Dragon to deliver cargo to the International Space Station , though no commercial manned missions are currently under way .

While putting money into renewed human space flight efforts , the proposal cuts scientific research , particularly the study of the other planets in our solar system . Planetary science takes a nearly $ 300 million hit compared to 2012 , the last year detailed figures were available .

NASA officials defended the cut , saying major projects like the Mars rover Curiosity and the upcoming MAVEN probe to study the Martian upper atmosphere are already past their most expensive phases .

`` But of course we 'll be ramping up again as we approach 2020 and the next Mars rover , '' said Beth Robinson , the agency 's chief financial officer .

Bolden said NASA 's Mars research is the biggest part of the planetary science budget .

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NEW : Asteroid research will help defend Earth , NASA chief says

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NASA 's $ 17.7 billion budget request is 1 % smaller than current funding

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It includes $ 105 million on research and plans to capture an asteroid

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The agency hopes to resume human space missions by 2017